Valve stem grinder



March 21, 1939. H c, PRESTON 2,151,528

VALVE STEM GRINDER Filed Feb. 14, 1956 2 Shets-Sheet l IIIIINIIIIIIHMarch 21, 1939. c. PRESTON 7 2,151,528

VALVE STEM GRINDER Patented Mar. 21, 1939 lack & Decker ManufacturingCompany, a corporation of Maryland Application February M, 1936, SerialNo. 63,85?

8 illlaims.

a The invention relates to apparatus for grinding the end surfaces ofvalve stems to determine their length, and .for ascertaining the properadjustment of the apparatus for each operation,

While the apparatus is capable of more general application to new workand to other types of valve, they are particularly adapted tothetreatment of internal combustion motor valves, after regrinding thevalve seats and resurfacing the valve.

The operation for which the grinding apparatus of the invention has beendevised is a step in the repair of internal combustion motors in whichno adjustment of the valve tappets is prcvided, making it necessaryafter each valve retacing and valve seat grinding job to remove somematerial from the lower end of the valve stem, in order to maintain, inthe closed position ,ofthe valve, the proper relation between the tappetand the end of the valve stem and between the valve and its seat, sothat closing of the valve at all motor temperatures is insured.

The apparatus may also be employed whenfor any reason it is notdesirable to change the valve tappet adjustment and in the assembling ofnew motors, particularly of the type first above identitled.

In the accompanying drawings I have illustrated an apparatus embodyingthe features of my invention in the preferred form.

In the drawings: Figure 1 is a front elevation of the grinding wheel andthe means for positioning and holding the valve and presenting it to thegrinding wheel,

, for grinding the end of the valve stem.

Figure 2 is a fragmentary end elevation of the same looking from theright in Figure 1.

Figure 3 is a fragmentary view corresponding to Figure 1 illustratingthe valve holding or clamping and positioning agencies in their relationto the grinding wheel and the manner of adjusting them to give theproper length of stand for a job which has been tested for this purposein accordance with the invention.

r v Figure 4 shows the apparatus of Figures 1, 2

and 3 assembled for operation, in connection with a valve resurfacingmachine. This arrangement may be chosen for convenience in performingsuccessively the operation of resurfacing the valves and grinding theends of their stems to reduce the stems to the proper length.

Figure 5 is an elevation of the valve stem gage in position in themotor, the surrounding portions of which are shown fragmentarily insections, the upper end of this tappet being shown in elevation.

Referring to the drawings by numerals, each of which is used to indicatethe same or similar parts in the different figures, the constructionments of the invention ,comprises a grinding wheel l, a swinging head,2, a valve stem gage construction 3 and a valve seating surfacepositioning abutment t.

More particularly described, the drawings show the grinding wheel l,which may be driven in any suitable manner, secured to the grindingwheel shaft 5 of a valve resurfacing machine by means of a nut it whichengages a threaded shaft end ll. While the apparatus of the invention isfor convenience combined with a valve resuriacer, it may also beconstructed as a separate unit or in any suitable arrangement. The outerflat surface 3 of the wheel I! in regular practice is at right angles tothe shaft axis. The grinding wheel 9 is preferably removable so it cantake the place -of some other removable agency as a brush or under.

Seated in a recess it in the machine frame or casing 9 parallel to theshaft 5 is an arbor Ill on which the swinging head 2 oscillates. Forthis purpose the head 2 is formed on the end of an arm H and onthe'opposite end of the arm ii there is a boss l2 containing bearing l2,which is free to slide on the arbor ID in the direction of its lengthand to oscillate about the axis of said arbor. Between the bearing boss12 and a collar I I, which encircles the arbor ID and is pinnedthereto'at M, a spring I5 is coiled about the arbor bearing at one endagainst the collar l4 and at the other end against a washer l5 whichencircles the shaft and rests against the bearing boss l2.

The bearing boss l2 with its arm II and the swinging head 2 are held inposition against'the pressure of spring |5 in any suitable manner butpreferably by a nut 16 which engages a fine thread H on the arbor I0near its outer end. The periphery of the nut as shown is marked withgraduations l8 which read in connection with a corresponding zero markor Vernier 19 on a washer 20 keyed to the, arbor. The nut I6 is referredto herein as a micrometer nut.

The swinging head 2 is grooved at 22 in parallel relation with the shaft5 and arbor l0 and a set screw 24 is threaded through the head 2, at theupper side of the groove, entering the groove,

which is shown as of rectangular cross section,

on the diagonal.

The head 2 is also bored at 25 parallel to groove 22 and shaft 5, and inthis bore 25 the stem 26 of the inclined abutment l is slldably mounted:It will be noted that both groove 22 and hole 25 are seats havingguiding surfaces parallel to the axis of wheel I. While the abutment 4is shown as having a conical end 21, this is mainly for convenience ofmanufacture, but it is at least desirable that this abutment bear thesame angle of inclination as the valve seating surface 28. The abutment4 is held in any desired position of adjustment by means of a set screw29. The heads of set screws 24 and 29 and micrometer nut l6 arepreferably knurled as shown, and shaft 5 is driven by a belt 30,engaging pulley 3| on said shaft, the belt being driven from anysuitable source of power as an electric motor not shown which drives thevalve refacer 9'.

Referring to Figure 5, the setting of abutment 4 to give the properlength of valve stem for any particular valve and seat is determined bymeans of a rod or gage stem 35 and sleeve 36 slidably mounted on thestem. The stem is shown as round, and any member which is adjustablealong the stem and adapted to support a dummy valve may be substitutedfor the sleeve. In the form shown the sleeve 36 is secured in adjustedposition on the stem 35 by a set screw 31 and is provided with a dummyvalve head 38 having a valve head seating surface 39 of the same angleas that of the valve being treated and adapted to contact the valve seatsurface 42 which is ground tothe same angle as valve head surface 39 andvalve seating surface 28. The guide portion 40 of the sleeve 36 isadapted to enter into the valve stem guide opening 4| of the motorcasting 50 till the valve head surface 39 contacts seat 42. The guideportion 40 may be provided with a bushing 43 which fits the opening 4|and is secured by means of a set screw 44. Spring ring 45 prevents thebushing 43 from dropping down into the motor in case it should becomeloosened.

In the operation of reducing a valve stem to the proper length, afterresurfacing the valve and grinding the seat, the shaft of the engine orlntemal combustion motor is turned till the tappet 46, Figure 5, of thevalve being treated, is in its lowermost position. This may be mosteasily ascertained by means of the gage stem or rod 35 which is guidedby the sleeve 36 which is first inserted through the valve seat 42 intothe valve guide opening 4| as just described with the seating surface 39of valve head 38 in contact with the valve seat surface 42 and the guideportion centered and aligned with the valve seat axis. To this end itmay either fit the valve stem guide opening 4| or be bushed to fit it,or it may be otherwise centered and aligned. The thumb screw 31 beingloosened so that the rod or gage stem 35 is free to move up and down,the bottom position of tappet 46 is easily ascertained by the positionof the stem. With the parts in this position, the gage stem 35 restingon tappet 46 in its lowermost position, seat surface 39 resting on seatsurface 42 and guide portion 40 centered and aligned with the axis ofthe valve seat, the screw 31 is tightened and the entire valve stem gageconstruction 3 as assembled with the screw 31 still tightened iswithdrawn from the position illustrated in Figure 5 and transferred tothe swinging head 2 as shown in Figure 3. In this second position thegage stem 35 rests in the longitudinal comer 22' of groove 22 with itsaxis parallel to the axis of shaft 5 and substantially intersecting theline of the axis of clamping screw 24, what was formerly the lower endof rod or gage stem 35 bearing against the fiat radial surface 9 ofgrinding wheel i. with the parts in this position as illustrated inFigure 3 the screw 24 is tightened.

The stem 24 of the inclined abutment 4 is free to slide in the, head 2,the thumb screw 29 being loosened for this purpose. The inclinedabutment is therefore easily moved to the left of the valve head 36 soas not to interfere with the proper location of the valve stem gageassembly 3. When the latter has been clamped as above stated bytightening the screw 24 with the end of gage stem 35 in contact withgrinding whee1 l and parallel to the shaft 5, the inclined abutment 4 ismoved to the right till its inclined surface 21 is in close contact withthe valve head seating surface 39. Then the screw 29 is tightened withthe parts in this position.

Then the screw 24 is loosened and the valve stem gage assembly 3 isremoved from the swinging head 2. The head 2 is next swung about thearbor Ill out of alignment with the grinding wheel I and the valve 41having been refaced as to seating surface 28 is clamped in the head 2 inplace of gage assembly 3 this being the valve from the seat 42 to whichthe valve stem gage was applied after the seat had been ground. Toproperly locate the valve 41, its stem 48 is placed in the corner 22' ofthe groove 22 with the seating surface 28 of the valve in close contactwith the inclined surface 21 of the abutment 4 adjusted and clamped asabove described. The screw 24 is then tightened clamping the valve 41 inthe position described in which the axis of the valve 41 and stem 48 isparallel to and with the axis of the grinding wheel I. By grinding thevalve stem in this position the stem would be just long enough to engagethe tappet 46 in its lowest position, with the valve seated, and withthe parts all remaining at one temperature throughout the process. Toprovide for seating at other temperatures, particularly when the motoris at normal running temperature or at a higher temperature, a slightclearance must be provided at the normal atmosphere temperature at whichthe grinding is done. The micrometer nut l6 and screw thread I! areprovided for this purpose, and the setting of the apparatus for thegrinding step is completed by turning the nut l6 to the rightsufilciently to move the bearing boss l2 tothe left to the amount of thedesired clearance -which is ordinarily about .008.

To complete the operation, the grinding wheel I being in rotation, thehead 2 is swung about the arbor i0 away from the observer in Figures 3and 4, and the operation of the grinding wheel removes the end portionof the valve stem up to the plane of the wheel face 8, which may bedefined as the radially disposed side surface of the wheel. This reducesthe valve to the right length to cause the valve to open at the righttime and to permit full and complete contact at the time of closing atany and all running temperatures.

The operation briefly stated consists in employing the gage to determinethe relation between the valve seat and the tappet in its bottomposition and clamping the gage in the head 2 to determine the positionof abutment 4. The valve is then clamped in the seat or groove 22 inplace of the gage, its position being determined by the abutment and theseat. Then its lower end is ground to the right length.

I have thus described specifically and in detail the apparatus of myinvention in the preferred form in order that the method ofconstructing, applying, operating and using the invention may be fullyunderstood, however, the specific terms herein are used descriptivelyrather than in a limiting sense, the scope of the invention beingdefined in the claims.

What I claim asnew and desire to secure by Letters Patent is:

Ill

1. The combination with a grinding wheel and means for rotating the sameof a head mounted to swing in a plane at right angles'to the grindingwheel axis, across the face of the wheel, the head having a seat for avalve stem and a seat for the shank of an abutment, both said seatshaving guiding surfaces for the said stem and shank, parallel to theaxis of said wheel, whereby the said stem and shank are guided andsupported in parallelism with said axis, clamping means for each saidseat and an abutment having a surface adapted to engage the seatingsurface of a valve, the stem of which is clamped in said valve stemseat, the abutment having a shank adapted to slide and be clamped in thesecond said seat.

2. The combination with a grinding wheel and means for rotating the sameof a head mounted to swing in a plane at right angles to the grindingwheel axis, across the face of the wheel, the head having a seat for avalve stem and a seat for the shank of an abutment, both said seatshaving guiding surfaces for the said stem and shank, parallel to theaxis of said wheel, whereby the said stem and shank are guided andsupported in parallelism with said axis, clamping means for each saidseat and an abutment having a surface adapted to engage the seatingsurface of a valve, the stem of which is clamped in said valve stemseat, the abutment having a shank adapted to slide and be clamped in thesecond said seat, and the same being adapted for use with a separatedetached gauge which is clamped in the said swinging head in place ofthe valve to determine the position of the said abutment in accordancewith the relation of the tappet in bottom position to the valve seat andmeans providing for the movement of the head toward the wheel todetermine the valve stem clearance.

3. The combination with a grinding wheel and means for rotating the sameof a head mounted to swing in a plane at right angles to the grindingwheel axis, across the face of the wheel, the head having a seat for avalve stem and a seat for 'an abutment, both said seats having guidingsurfaces for the said stem and abut ment, parallel to the axis of saidwheel whereby the said stem and abutment are guided and supported inparallelismwith said axis, clamping means for each said seat and anabutment having a surface adapted to engage the seating surface of avalve, the stem of which is clamped in said valve stem seat, theabutment being adapted to slide and be clamped in relation to the secondsaid seat, the same being adapted for use with a gauge which is insertedin said head in place of the valve stem to determine the setting of saidabutment in correspondence with the distance from the valve seat to thetappetand means providing for the adjustment of the head toward and fromthe grinding plane.

4. The combination with a grinding wheel and means for rotating the sameof a head mounted to swing in a plane at right angles to the grindingwheel axis, across the face of the wheel, the head having a seat for avalve stem and a seat for an abutment, both said seats having guidingsurfaces for the said stem and abutment, parallel to the axis of saidwheel whereby the said stem and abutment are guided and supported inparallelism with said axis, clamping means for each said seat and anabutment having an outside surface inclined to. engage the seatingsurface of a valve, the stem of which is clamped in. said valve stemseat, the abutment being adapted to slide and to be clamped in relationto the second said seat, the same being adapted for use with a gaugewhich is set in accordance with the relation between a tappet in itsbottom position and the corresponding valve seat and is inserted in saidhead in place of the valve stem to determine the setting of saidabutment the head having a shaft about which said swing takes place, andmeans providing for adjustment of the head along said 1 shaft todetermine the valve stem clearance.

5. The combination with a grinding member and means for moving the "sameto provide a grinding plane, of a head mounted to move in parallelismwith said grinding plane across said grinding plane, the head having aseat for a valve stem and a seat for the shank of an abutment both saidseats having guiding means for said stem and shank at right angles tosaid grinding plane, clamping means for each said seat and an abutmenthaving a surface adapted to engage the seating surface of a valve thestem of which rests in said valve stem seat the abutment havin a shankadapted to slide and be clamped in the second seat. a

6. The combination with a grinding member and means for moving the sameto provide a grinding plane, of a head mounted to move in parallelismwith said grinding plane across said grinding plane, the head having aseat for a valve stem and a seat for the shank of an abutment both saidseats having guidingmeans for said stem and shank at right angles tosaid grinding plane, clamping means for each said seat and an abutmenthaving an inclined surface adapted to engage the seating surface of avalve, the stem. of which is in said valve stem seat, the abutmenthaving a shank adapted to slide and be clamped in the second seat, andmeans for adjusting said head toward and from said grinding plane todetermine the clearance of the valve being ground.

.7. The combination with a grinding member and means for moving the sameto provide a grinding plane, of a head mounted to move in parallelismwith said grinding plane across said grinding plane, the head having aseat for a valve stem and a seat for the shank of an abutment, both saidseats having guiding means for said stem and shank at right angles tosaid grinding plane, clamping means for said seats and an abutmenthaving a conical surface adapted to engage the seating surface of avalve having its stem in said valve stem seat the abutment having ashank adapted to slide -and be clamped in the second seat.

8. The combination with a. grinding member and means for moving the sameto provide a grinding plane of a head having a shaft substantially atright angles to said plane upon which the head is mounted to swingacross said grinding plane, a. micrometer screw for moving said headalong said shaft toward said grinding plane said head having a seat fora valve stem and a seat for the shank of an abutment both said seatshaving guiding means for said stem and said shank at right angles tosaid grinding plane, clamping means for said seats and an abutmenthaving a surface adapted to engage the seating surface of a valve thestem of which is clamped in said valve stem seat the abutment having ashank adapted to slide and be clamped in the second said seat. v

HENRY C. PRESTON.

